added unit tests

0.380 seconds for 100 FFA folds of 32x2500 array
Removed FFAButterfly, indecies are computed on the fly
Turned FFAGroupShiftAdd into a C-style function
Removed array creation from FFAGroupShiftAdd

0.200 seconds for 100 folds of a 32x2500 array
Wrote the core functions in C
FFA_cext.pyx is the cython wrapper

Does 100 32x2500 folds in 0.17 seconds ~200 MFlops
setup.py includes new modules, minor changes to everything else
made a profiling function main()
resolved conflict